From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Mark Rutland <mark.rutland@arm.com>, Andrew Lunn <andrew@lunn.ch>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Jason Cooper <jason@lakedaemon.net>,
devicetree@vger.kernel.org, Stephen Boyd <sboyd@kernel.org>,
linux-pci@vger.kernel.org,
Gregory Clement <gregory.clement@bootlin.com>,
linux-kernel@vger.kernel.org,
Maxime Chevallier <maxime.chevallier@bootlin.com>,
Nadav Haklai <nadavh@marvell.com>,
Antoine Tenart <antoine.tenart@bootlin.com>,
Rob Herring <robh+dt@kernel.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
sudeep.holla@arm.com, Bjorn Helgaas <bhelgaas@google.com>,
linux-arm-kernel@lists.infradead.org,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Subject: Re: [PATCH 05/12] PCI: aardvark: add suspend to RAM support
Date: Tue, 18 Dec 2018 11:54:43 +0100 [thread overview]
Message-ID: <28619896.152T6JUIHS@aspire.rjw.lan> (raw)
In-Reply-To: <20181217155426.71058a03@xps13>
On Monday, December 17, 2018 3:54:26 PM CET Miquel Raynal wrote:
> Hi Rafael,
>
> "Rafael J. Wysocki" <rjw@rjwysocki.net> wrote on Thu, 13 Dec 2018
> 22:50:51 +0100:
>
> > On Thursday, December 13, 2018 3:30:00 PM CET Miquel Raynal wrote:
> > > Hi Lorenzo,
> > >
> > > > > If that's really the case, then I can see how one device and it's
> > > > > children are suspended and the irq for it is disabled but the providing
> > > > > devices (clk, regulator, bus controller, etc.) are still fully active
> > > > > and not suspended but in fact completely usable and able to service
> > > > > interrupts. If that all makes sense, then I would answer the question
> > > > > with a definitive "yes it's all fine" because the clk consumer could be
> > > > > in the NOIRQ phase of its suspend but the clk provider wouldn't have
> > > > > even started suspending yet when clk_disable_unprepare() is called.
> > > >
> > > > That's a very good summary and address my concern, I still question this
> > > > patch correctness (and many others that carry out clk operations in S2R
> > > > NOIRQ phase), they may work but do not tell me they are rock solid given
> > > > your accurate summary above.
> > >
> > > I understand your concern but I don't see any alternative right now
> > > and a deep rework of the PM core to respect such dependency is not
> > > something that can be done in a reasonable amount of time.
> >
> > Maybe you don't need to rework anything. :-)
> >
> > Have you considered using device links?
>
> Absolutely, yes :) I am actively working on it in parallel, you can
> check the third version there [1]. Stephen Boyd has a slightly
> different idea of how it should be done, I will propose a v4 this week,
> I can add you in copy if you are interested!
>
> Anyway, there is one thing that is still missing:
> * Let's have device A that requests clock B
> * With the device link series, A is linked (as a child) to B.
> * A suspend/resume hooks handle things in the NOIRQ phase.
Why do you need them to run in the "noirq" phase in the first place?
> * B suspend/resume hooks handle things in the default phase.
>
> What I expected during a suspend:
> 1/ ->suspend_noirq(device A)
> 2/ ->suspend(clock B)
This expectation is not in agreement with the documented suspend code flow,
however.
Each phase of it is carried out for *all* devices completely before getting
to the next phase, "prepare" first, then "suspend", "suspend_late" and
"suspend_noirq", in this order.
> Unfortunately, device links do not seem to enforce any priority between
> phases (default/late/noirq) and what happens is:
> 1/ ->suspend(B)
> 2/ ->suspend_noirq(A)
> Which has no sense in my case. Hence, I had to request the clock
> suspend/resume callbacks to be upgraded to the NOIRQ phase as well (I
> don't have a better solution for now). This is still under discussion
> in a thread you have been recently added to by Bjorn, see [2].
>
> So when I told you I was not confident in "reworking the PM core to
> respect such dependency", this is what I was referring to. I am
> definitely ready to help, but I don't feel I can do it alone.
>
> [1] https://www.spinics.net/lists/linux-clk/msg32824.html
> [2] https://marc.info/?l=linux-pm&m=154465198510735&w=2
The rework you seem to be talking about is not possible, I'm afraid.
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next prev parent reply other threads:[~2018-12-18 10:55 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-23 14:18 [PATCH 00/12] Bring suspend to RAM support to PCIe Aardvark driver Miquel Raynal
2018-11-23 14:18 ` [PATCH 01/12] PCI: aardvark: configure more registers in the configuration helper Miquel Raynal
2018-11-23 14:18 ` [PATCH 02/12] PCI: aardvark: add reset GPIO support Miquel Raynal
2018-11-23 14:18 ` [PATCH 03/12] PCI: aardvark: add PHY support Miquel Raynal
2018-11-23 14:18 ` [PATCH 04/12] PCI: aardvark: add clock support Miquel Raynal
2018-11-23 14:18 ` [PATCH 05/12] PCI: aardvark: add suspend to RAM support Miquel Raynal
2018-12-03 10:27 ` Lorenzo Pieralisi
2018-12-03 15:38 ` Miquel Raynal
2018-12-03 17:18 ` Lorenzo Pieralisi
2018-12-03 19:19 ` Stephen Boyd
2018-12-03 22:00 ` Rafael J. Wysocki
2018-12-03 22:18 ` Miquel Raynal
2018-12-04 9:45 ` Lorenzo Pieralisi
2018-12-04 21:42 ` Rafael J. Wysocki
2018-12-05 11:00 ` Lorenzo Pieralisi
2018-12-11 14:16 ` Lorenzo Pieralisi
2018-12-13 9:00 ` Stephen Boyd
2018-12-13 10:53 ` Lorenzo Pieralisi
2018-12-13 14:30 ` Miquel Raynal
2018-12-13 14:52 ` Lorenzo Pieralisi
2018-12-13 21:50 ` Rafael J. Wysocki
2018-12-17 14:54 ` Miquel Raynal
2018-12-18 10:54 ` Rafael J. Wysocki [this message]
2018-12-18 14:14 ` Miquel Raynal
2018-11-23 14:18 ` [PATCH 06/12] dt-bindings: PCI: aardvark: describe the reset-gpios property Miquel Raynal
2018-12-11 21:44 ` Rob Herring
2018-11-23 14:18 ` [PATCH 07/12] dt-bindings: PCI: aardvark: describe the clocks property Miquel Raynal
2018-12-11 21:44 ` Rob Herring
2018-11-23 14:18 ` [PATCH 08/12] dt-bindings: PCI: aardvark: describe the PHY property Miquel Raynal
2018-12-11 21:44 ` Rob Herring
2018-11-23 14:18 ` [PATCH 09/12] ARM64: dts: marvell: armada-37xx: declare PCIe reset pin Miquel Raynal
2018-11-23 14:18 ` [PATCH 10/12] ARM64: dts: marvell: armada-3720-espressobin: declare PCIe reset GPIO Miquel Raynal
2018-11-23 14:18 ` [PATCH 11/12] ARM64: dts: marvell: armada-37xx: declare PCIe clock Miquel Raynal
2018-11-23 14:18 ` [PATCH 12/12] ARM64: dts: marvell: armada-3720-espressobin: declare PCIe PHY Miquel Raynal
2018-11-26 14:50 ` [PATCH 00/12] Bring suspend to RAM support to PCIe Aardvark driver Bjorn Helgaas
2018-11-30 13:12 ` Miquel Raynal
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